Over-the-air test system as well as method for measuring the over-the-air performance of a device under test

ABSTRACT

An over-the-air test system for measuring the radiation performance as a function of temperature of a device under test is described, wherein the device under test has at least one antenna unit and at least one radio frequency circuit. The over-the-air test system comprises a measurement antenna unit, a measurement unit for at least one of signal generation and signal analysis, an enclosure that provides an internal space for accommodating the device under test for testing purposes in a sealed manner, and an atmosphere conditioning system that is configured to adapt the atmosphere within the internal space. The enclosure comprises at least one sealable opening via which the internal space is connectable with the atmosphere conditioning system to adapt the atmosphere within the internal space for the testing. Further, a method for measuring the over-the-air performance of a device under test is described.

FIELD OF THE DISCLOSURE

Embodiments of the present disclosure relate generally to anover-the-air test system for measuring the radiation performance as afunction of temperature of a device under test. Further, embodiments ofthe present disclosure generally relate a method for measuring theover-the-air performance of a device under test as a function oftemperature of the device under test.

BACKGROUND

Over-the-air measurements (OTA measurements) are inter alia done toperform telecommunication standard conformance tests for verifying therespective radiation properties of the device under test. For instance,the device under test is tested for the telecommunication standard 3GPPby performing three-dimensional OTA measurements.

In times of an increasing number of wireless communication applicationsbeing exposed to different ambient conditions (atmospheres) such asvarying temperatures, there is a growing need of an over-the-air testsystem as well as a method for investigating a device under test withrespect to its temperature behavior.

In the state of the art, methods and systems are known that are used fortesting an antenna unit of a device under test wherein a static chamberis positioned around the antenna unit of the device under test wherein acertain atmosphere (ambient conditions) is applied for the testing.Hence, the device under test is only partly covered by the chamberresulting in a leakage of the atmosphere applied which is inefficient onthe one hand and might impair the validity of the testing on the otherhand. In addition, test scenarios comprising several different testscannot be applied due to the instable atmosphere.

In addition, these systems and methods cannot be used forthree-dimensional OTA measurements due to the arrangement of the chamberand the device firmly connected to the chamber for adapting theatmosphere within the chamber.

Further, the influence of a radio frequency circuit connected to theantenna unit is not tested by those systems and methods as only theantenna unit is encompassed by the respective chamber providing acertain testing atmosphere. Therefore, the impact of the temperature onthe whole device under test is not investigated in total.

Accordingly, there is a need for an over-the-air test system as well asa method ensuring high validity of the measurement results whilemeasuring the impact of temperature on the device under test in total,in particular the respective radio frequency circuit of the device undertest processing the respective signals transmitted and/or received bythe antenna unit.

SUMMARY

Embodiments of the present disclosure provide an over-the-air testsystem for measuring the radiation performance as a function oftemperature of a device under test having at least one antenna unit andat least one radio frequency circuit, wherein the over-the-air testsystem comprises:

a measurement antenna unit;

a measurement unit for at least one of signal generation and signalanalysis;

an enclosure that provides an internal space for accommodating thedevice under test for testing purposes in a sealed manner; and

an atmosphere conditioning system that is configured to adapt theatmosphere within the internal space,

wherein the enclosure comprises at least one sealable opening via whichthe internal space is connectable with the atmosphere conditioningsystem to adapt the atmosphere within the internal space for thetesting.

Further, embodiments of the present disclosure provide a method formeasuring the over-the-air performance of a device under test as afunction of temperature of the device under test, comprising thefollowing steps:

providing a device under test with at least one antenna unit and atleast one radio frequency circuit;

placing the device under test in an enclosure;

adapting the atmosphere in the enclosure, for example the temperatureand/or the pressure, by guiding air into the enclosure and/or by guidingair from the enclosure via an atmosphere conditioning system until apredetermined atmosphere is reached;

sealing off the enclosure by closing at least one opening used foradapting the atmosphere in the enclosure; and

performing the over-the-air measurement.

Accordingly, the temperature dependency of a device under test used fortelecommunication purposes can be investigated more accurately and withhigher validity by exposing the whole device under test to therespective atmosphere (ambient conditions). Thus, the device under test,comprising at least one antenna unit and at least one radio frequencycircuit (RF circuit), is located completely within the enclosure suchthat the radio frequency circuit is also exposed to the respectiveatmosphere. Hence, the part of the device under test processing thesignals received and/or transmitted via the antenna unit is also exposedto the respective atmosphere in order to investigate the behavior of thewhole device under test.

Since the whole device under test is located within the enclosure, abaseband unit may also be located within the enclosure as being part ofthe device under test.

Further, the efficiency of the testing is improved since the openingused for adapting the atmosphere for testing purposes is sealed offduring the testing so that it is ensured that the atmosphere, forinstance the pressure and/or temperature, within the internal space canbe maintained for a long time, for example in a stable manner. In otherwords, the air within the internal space does not escape as the internalspace is closed or rather sealed off with respect to the environment.

For instance, the at least one sealable opening comprises a check valvepermitting gas flow only into one direction.

As the at least one opening is established as a sealable opening, it isensured that the atmosphere within the internal space can be adapted fortesting purposes easily, namely when the at least one opening is notsealed off. In addition, the atmosphere can be maintained constantduring the testing when the device under test is accommodated in theenclosure by sealing off the at least one opening. Thus, the deviceunder test is located within the enclosure in a sealed manner during thetesting.

In addition, the atmosphere conditioning system is not connected to theenclosure during the testing of the device under test. This ensures thatthe atmosphere conditioning system does not affect the atmosphere duringthe testing as not gas exchange is enabled.

In other words, the atmosphere conditioning system is a connectableatmosphere conditioning system as it can be connected to the enclosurevia the sealable opening for adapting the atmosphere within theenclosure.

In general, the over-the-air test system has at least two differentoperation modes.

In the first operation mode, an atmosphere conditioning operation mode,the atmosphere conditioning system is connected to the enclosure, forexample via the at least one sealable opening, in order to adapt theatmosphere within the internal space. Hence, the at least one sealableopening enables a gas exchange between the internal space and theatmosphere conditioning system.

In the second operation mode, the testing operation mode, the atmosphereconditioning system is disconnected from the enclosure wherein the atleast one sealable opening is sealed off such that the device under testis accommodated in the enclosure in a sealed manner. The atmosphereestablished in the internal space cannot escape due to the sealed offopening.

In other words, in the first operation mode, namely the atmosphereconditioning operation mode, the atmosphere conditioning system isconnected to the enclosure, for example via the at least one sealableopening.

In the second operation mode, namely the testing operation mode, theatmosphere conditioning system is disconnected from the enclosurewherein the at least one sealable opening is sealed off.

Accordingly, the over-the-air test system corresponds to aself-contained climate system for over-the-air measurements of thedevice under test.

In general, the over-the-air test system (OTA test system) is configuredto perform one-dimensional, two-dimensional as well as three-dimensionaltesting of the radiation performances of the device under test since thewhole device under test is located within the enclosure providing thedesired atmosphere for the device under test.

As the device under test is completely accommodated in the enclosure,the enclosure completely covers the entire device under test.

The measurement antenna unit is connected to the measurement unit suchthat signals may be exchanged between the measurement antenna unit andthe measurement unit wherein the signals may correspond to signalsreceived via the measurement antenna unit and/or signals generated andtransmitted via the measurement antenna unit.

At least the measurement antenna unit may be configured to be movable,rotatable, tiltable, pivotable, or any combination thereof.

The atmosphere conditioning system is generally located outside of theenclosure.

The atmosphere conditioning system is configured to be driven relativeto the enclosure.

The atmosphere conditioning system is configured to be driven towardsthe enclosure to couple with the enclosure via the sealable opening,namely in the atmosphere conditioning operation mode. Further, theatmosphere conditioning system is configured to be driven away from theenclosure to decouple from the enclosure, namely in the testingoperation mode.

According to an aspect, the enclosure is configured such that a gap isprovided between the device under test and the inner surface of theenclosure. The inner surface of the enclosure does not contact thedevice under test. The device under test may be positioned on a stand orplatform defining a testing position for the device under test withinthe enclosure. The enclosure confines the internal space which might befilled with air of a certain temperature and/or pressure such that it isensured that the device under test can be tested at differenttemperatures and/or pressures.

The platform defining the testing position for the device under test maybe connected with the enclosure in order to define a sealed space forthe device under test.

Moreover, the atmosphere conditioning system may comprise a control unitwhich controls the atmosphere within the internal space. The atmosphere(or rather the ambient conditions) of the internal space may be variedby the atmosphere conditioning system in a controlled manner such thatthe temperature and/or the pressure the device under test is exposed tocan be varied in a desired manner during a test scenario applied. Thetest scenario may comprise several different test steps defined bydifferent testing conditions, for example different atmospheres. Inorder to obtain the predetermined ambient conditions (atmospheres), thecontrol unit controls the atmosphere conditioning system appropriately.

The atmosphere conditioning system may comprise a blower and/or atemperature conditioning unit such as a heating unit and/or a coolingunit.

In some embodiments, the atmosphere conditioning system comprises apiping system for guiding air from the internal space and/or for guidingair to the internal space. For instance, the piping system may beconnected with the heating unit and/or the blower for blowing the airinto the internal space and/or sucking the air out of the internal spacedepending on the test scenario applied. The piping system may have aninterface interacting with the sealable opening such that theconditioned air (heated and/or pressurized) can be guided into theinternal space for adapting the atmosphere in a desired manner. Theinterface of the piping system may be established such that the sealableopening is automatically opened when the interface comes into contactwith the opening.

Generally, the at least one opening may be configured to process an airstream into the internal space and/or to process an air stream from theinternal space. As mentioned above, the at least one opening maycomprise a check valve ensuring that the air stream may only flow intoone direction. For adapting the atmosphere within the internal space, atleast two openings may be provided.

The at least one opening may also be configured to enable an air streamin both directions depending on the operating status of the atmosphereconditioning system, for example the blower, and/or the pressurerelationships, namely the atmosphere pressures within the internal spaceand of the environment.

Furthermore, the enclosure may be made of a radio frequency neutralmaterial. The radio frequency neutral material corresponds to a radiofrequency transparent material. This material ensures that theover-the-air measurements of the device under test encapsulatedcompletely within the enclosure can be performed appropriately since themeasurement antenna unit used for the tests is located outside theenclosure. Thus, the electromagnetic waves may penetrate through theenclosure due to the radio frequency neutral material. The radiofrequency neutral material ensures that the enclosure has no influenceon the radio frequency signals or rather the electromagnetic waves usedfor the measurements.

According to an embodiment, the enclosure comprises an inflatable layer,for example a balloon-like layer. Thus, the pressure in the internalspace can be adapted appropriately since the appropriate layer, forexample the whole enclosure, may be inflated when the pressure isincreased.

Furthermore, the enclosure may have at least two layers spaced apartfrom each other such that an air gap is provided between both layers.The air gap provided between both layers reduces condensation effects asthe air gap acts as an insulation layer. Hence, the measurement accuracyand its validity are increased simultaneously. Moreover, condensationeffects can be reduced or rather eliminated.

In addition, a positioning unit for the enclosure may be provided, forexample wherein the enclosure is placed on the positioning unit. Thepositioning unit may be a movable one such that the whole device undertest located within the enclosure during the testing can be movedappropriately.

For instance, the positioning unit is configured to enable athree-dimensional movement such that three-dimensional OTA measurementscan be done easily. For this purpose, the positioning unit defines atesting position for the device under test. The testing position and thedevice under test located there may be rotated about an axis by thepositioning unit. Further, the positioning unit may allow a tiltingmovement as well as a height adjustment.

Generally, the positioning unit may be configured to tilt, pivot and/orrotate the enclosure placed on the positioning unit. In other words, thepositioning unit is configured to manipulate the position of the deviceunder test in roll, azimuth and/or elevation such that three dimensionalmeasurements can be performed appropriately.

The positioning unit may be directly connected to the enclosure, forexample forming a part of the enclosure. Thus, the enclosure correspondsto a cover that is connected to a platform of the positioning unit in asealed manner such that the device under test is accommodated in theenclosure in a sealed manner.

Alternatively, the positioning unit providing a platform or rather thetesting position for the device under test penetrates partly through theenclosure in a sealed manner. Hence, the device under test is onlymoved, tilted and/or rotated via the positioning unit within theenclosure.

Moreover, the enclosure comprises an interface panel for establishingconnections between the device under test and periphery devices, forexample cable connections. The interface panel may comprise socketsand/or connectors for power cables, fiber optics and/or radio frequencyconnectors. The respective cables and/or connectors may be used forcontrol signals as well as signal pass-throughs. Hence, the device undertest being encapsulated by the enclosure can be controlled via theinterface panel appropriately even though the enclosure is sealed offduring the testing.

The periphery devices may be the members of the measurement unit usedfor signal generation and/or signal analyzers or any other measurementequipment.

The interface panel may be provided at the side facing to thepositioning unit, for example the platform on which the enclosure isplaced for moving, rotating and/or tilting.

Furthermore, the measurement antenna unit may comprise at least one of asingle antenna, an antenna array and a hardware-based near-field tofar-field transform unit. Thus, different testing scenarios may beapplied due to the different measurement antenna unit used.

Moreover, the measurement antenna unit may comprise a plurality ofdifferent antennas, for instance an antenna array as well as a singleantenna, being used for different testing purposes. The appropriateantenna(s) may be selected depending on the testing purposes.

Further, the over-the-air test system may comprise a device under testthat has at least one antenna unit and at least one radio frequencycircuit. Hence, the device under test itself is part of the OTA testsystem.

For instance, the over-the-air test system also comprises an anechoicchamber. The measurement antenna unit as well as the device under testmay be assigned to the anechoic chamber, for example placed in thischamber. The anechoic chamber may be covered internally with radiofrequency absorbing material to reduce or even eliminate interferencesdisturbing the measurements.

According to an aspect, the over-the-air measurements (OTA) areperformed in one dimension, two dimensions or three dimensions. Thus,the radiation performance of the device under test can be obtained withhigh accuracy for all relevant application scenarios.

Furthermore, the atmosphere in the enclosure is re-adapted by connectingthe atmosphere conditioning system with the enclosure for ventilationand/or changing the atmosphere. Thus, the device under test placedwithin the enclosure may be exposed to different ambient conditions(atmospheres) subsequently. For this purpose, the enclosure is connectedwith the atmosphere conditioning system again in an appropriate manner.It is not necessary to open the enclosure completely as the atmosphereconditioning system is only connected to the enclosure via the sealableopening.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of theclaimed subject matter will become more readily appreciated as the samebecome better understood by reference to the following detaileddescription, when taken in conjunction with the accompanying drawings,wherein:

FIG. 1 shows schematically a representative embodiment of anover-the-air test system according to the present disclosure in atesting operation mode;

FIGS. 2a and 2b show a detail of the over-the-air test system of FIG. 1during an atmosphere conditioning operation mode and the testingoperation mode;

FIG. 3 shows an enclosure of the over-the-air test system according toan embodiment; and

FIG. 4 shows an enclosure of the over-the-air test system according toanother embodiment.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings, where like numerals reference like elements, is intended as adescription of various embodiments of the disclosed subject matter andis not intended to represent the only embodiments. Each embodimentdescribed in this disclosure is provided merely as an example orillustration and should not be construed as preferred or advantageousover other embodiments. The illustrative examples provided herein arenot intended to be exhaustive or to limit the claimed subject matter tothe precise forms disclosed.

In FIG. 1, an over-the-air test system 10 for measuring the radiationperformance of a device under test 12 is shown wherein the over-the-airtest system 10 (OTA test system) comprises a measurement device 14 thathas a measurement unit 16 for signal generation and/or signal analysisas well as a measurement antenna unit 18 that is connected to themeasurement unit 16 for transmitting the signal generated and/orreceiving a signal generated by the device under test 12.

Accordingly, the over-the-air test system 10 is generally configured totest the receiving properties as well as the transmission properties ofthe device under test 12.

As shown in FIG. 1, the measurement device 14 is at least partlymovable. For instance, the measurement antenna unit 18 is pivotable withrespect to the device under test 12 as indicated by the arrows. Inaddition thereto, the measurement device 14, for example the measurementantenna unit 18, can be moved linearly for adjusting the height orrotated about its axis.

Furthermore, the whole measurement device 14 can be moved with respectto the device under test 12 as mentioned above. Thus, the radiationperformance of the device under test 12 can be tested under differenttesting scenarios, for example radiation angles (impinging angles).

Further, the OTA test system 10 comprises an enclosure 20 that definesan internal space 22 which is used for accommodating the device undertest 12 during the testing as shown in FIG. 1. The internal space 22provided by the enclosure 20 corresponds to a sealed off space.

In the shown embodiment, the enclosure 20 comprises a first outer layer24 as well as a second inner layer 26 wherein both layers 24, 26 arespaced apart from each other such that an air gap 28 is establishedbetween both layers. This air gap 28 may be used for insulation purposesas will be described later.

In addition, the second inner layer 26 may be established by aninflatable layer such that the inner layer 26 is configured to adapt itsshape when it is inflated, for example the pressure within the internalportion of the enclosure 20 increases. Thus, the inner layer 26 mayexpand into the air gap 28 provided between both layers 24, 26 when theassociated space is inflated. Accordingly, the inner layer 26corresponds to a balloon-like layer.

In addition, the enclosure 20 is generally configured such that a gap isprovided between the device under test 12 and the inner surface of theenclosure 20 being defined by the inner surface of the inner layer 26 inthis embodiment. This gap is part of the internal space 22 that is usedfor accommodating the device under test 12. In general, the gap ensuresthat the inner surface of the enclosure 20, for example the one of theinner layer 26, does not entirely contact the device under test 12.

In addition, the enclosure 20 has at least one sealable opening 30 asshown in FIG. 1 that may established a connection between the internalspace 22 and the outer circumference of the enclosure 20 when theopening 30 is opened such that the atmosphere (ambient condition) withinthe internal space 22 can be adapted appropriately via the sealableopening 30.

Hence, the sealable opening 30 establishes an interface for adapting theatmosphere of the internal space 22 as will be described later.

For adapting the atmosphere within the internal space 22, theover-the-air test system 10 comprises an atmosphere conditioning system32 that is also shown in FIG. 1 on the right hand side. As shown in FIG.1, the atmosphere conditioning system 32 is not connected with theenclosure 20 since it is located apart from the enclosure 30 when theOTA system 10 is in the testing operation mode as shown in FIG. 1.

However, the atmosphere conditioning system 32 may be connected with theenclosure 20 for adapting the atmosphere within the internal space 22appropriately in another operation mode of the OTA system, theatmosphere adapting operation mode. Hence, the atmosphere conditioningsystem 32 is generally configured to adapt the atmosphere within theinternal space 22 when it is connected to the enclosure 20 via thesealable opening 30 as will be described later.

As shown in FIG. 1, the atmosphere conditioning system 32 comprises acontrol unit 34 that is connected to a blowing, cooling and/or heatingunit 36 which in turn is connected to a piping system 38 having aninterface 40 to be connected with the at least one sealable opening 30for adapting the atmosphere within the internal space 22. The blowing,cooling and/or heating unit 36 may be established by at least twodifferent sub-units, for instance a blower and a temperatureconditioning sub-unit.

Generally, the atmosphere conditioning system 32 may be configured toadapt the pressure and/or temperature within the internal space 22 byguiding air via the piping system 38. For instance, air is guided fromthe environment into the internal space 22 or air is sucked from theinternal space 22 and guided to the environment. In other words, theinternal space 22 may be inflated and/or deflated. Hence, the controlunit 34 may also control the direction of the air stream as well as thepressure within the internal space 22 appropriately.

The temperature of the atmosphere within the internal space 22 may alsobe controlled by the control unit 34 indirectly as the control unit 34controls the cooling and/or heating unit 36 of the atmosphereconditioning system 32 appropriately.

Generally, the enclosure 20 may comprise several sealable openings 30that might be configured to process an air stream only in one direction,namely an air stream into the internal space 22 or from the internalspace 22 to the environment. For this purpose, the respective sealableopening 30 may comprise a check valve.

However, the at least one sealable opening 30 may also be configured topermit gas flow in both directions such that the gas exchange may beestablished via the at least one opening 30.

As shown in FIG. 1, the device under test 12 comprises at least oneantenna unit 42 as well as at least one radio frequency circuit 44connected to the antenna unit 44. The whole device under test 12 islocated within the enclosure 20, namely within the internal space 22.Thus, the antenna unit 42 as well as the radio frequency circuit 44 bothare exposed to the same atmosphere within the internal space 22 as bothare located within the enclosure 20 in a sealed manner. In other words,the whole device under test 12, comprising the at least one antenna unit42 as well as the at least one radio frequency circuit 44, is testedunder the same ambient conditions (atmosphere), namely the one withinthe internal space 22 being adapted previously via the atmosphereconditioning system 32.

As the radiation performance of the device under test 12, namely thereceiving properties as well as the transmission properties, shall betested by the over-the-air test system 10, the enclosure 20 is made of aradio frequency neutral material to ensure that the electromagneticwaves may pass through the enclosure 20. Hence, the device under test 12and the measurement device 14 may interact with each other by exchangingelectromagnetic waves required for testing the radiation performance(s)of the device under test 12.

For connecting the device under test 12 within the enclosure 20, namelyduring the testing, an interface panel 46 is provided that is assignedto the inner space 22 and the outer space of the enclosure 20 such that(cable) connections or the like between the device under test 12 andperiphery devices of the OTA test system 10 can be established via theinterface panel 46.

The periphery devices may be power sources, signal sources or themeasurement device 14 itself.

Hence, the interface panel 46 may have connectors and/or sockets forcables, signal cables, power cables, fiber optics and/or radio frequencyconnectors wherein these members may be used for controlling purposesand/or signal pass-throughs. In some embodiments, the interface panel 46may be part of the enclosure 20.

In addition, the OTA test system 10 comprises a positioning unit 48 forthe enclosure 20 that may be positioned on the positioning unit 48 inorder to be moved or rotated appropriately for testing the radiationperformances under different angles. For instance, the positioning unit48 may be configured to perform three-dimensional movements (rotational,tilting, pivoting, swiveling and/or linear movements) which simplifiesmultiple-dimensional measurements of the radiation performances of thedevice under test 12 such as two- or three-dimensional measurements.

As shown in FIG. 1, the interface panel 46 is provided at the side ofthe enclosure 20 facing the positioning unit 48. For instance, theinterface panel 46 and the positioning unit 48 may establish by aplug-in interface in a sealed manner, for example a fixed one.

The whole enclosure 20 as well as the device under test 12 locatedtherein may be positioned on the positioning unit 48 for being moved,rotated, swiveled, pivoted and/or tilted during the testing, for examplethe testing scenario applied.

However, the positioning unit 48 may also comprise a platform defining atesting position for the device under test 12 wherein the platformpasses through the enclosure 20 in a sealed manner such that only theplatform and the device under test 12 is moved appropriately within theenclosure 20 that remains stationary in contrast thereto.

In FIGS. 2a and 2b , the OTA test system 10 is shown in its atmosphereconditioning operation mode (FIG. 2a ) as well as the testing operationmode (FIG. 2b ) in more detail.

In FIG. 2a , the atmosphere conditioning operation mode is shown inwhich the atmosphere within the internal space 22 is adapted by theatmosphere conditioning system 32 being connected to the enclosure 20.

For this purpose, the atmosphere conditioning system 32 is connected tothe enclosure 20 via the sealable opening 30 and the interface 40 of thepiping system 38. Thus, the piping system 38 is coupled to the enclosure20 such that air can be blown into the internal space 22 for increasingthe pressure and/or adapting the temperature within the internal space22 depending on the cooling and/or heating unit 36. Alternatively, theinternal space 22 may be deflated by sucking air from the internal space22.

Once the atmosphere within the internal space 22 has reached thepredetermined conditions, namely temperature and/or pressure, theenclosure 20 is sealed off by disconnecting the atmosphere conditioningsystem 32 from the enclosure 20 and closing or rather sealing off thesealable opening 30 as shown in FIG. 2b . For instance, the sealableopening 30 may seal off itself automatically when the interface 40 isbrought out of contact.

Thus, the atmosphere conditioning system 32 is no more connected to theenclosures 20 such that it is ensured that the movability of theover-the-air test system 10, for example the enclosure 20 and the deviceunder test 12 accommodated in the enclosure 20, is not impaired by theatmosphere conditioning system 32 during testing the device under test12. Accordingly, three dimensional movements such as tilting, swiveling,rotational and/or linear movements are possible.

Hence, the enclosure 20 and the whole device under test 12 accommodatedtherein positioned on the positioning unit 48 may be moved freely as theatmosphere conditioning system 32 is disconnected from the enclosure 20.

In FIGS. 3 and 4, two different embodiments of the enclosure 20 areshown. In FIG. 3, the enclosure 20 comprises a single layer enclosure 20being inflatable. In contrast thereto, the enclosure 20 shown in FIG. 4corresponds to the one shown in FIG. 1. The two layers 24, 26 as well asthe air gap 28 provided between them ensure that a thermal insulation isprovided. Moreover, condensation effects are reduced or even eliminatedwhich might influence the measurements.

Generally, the OTA test system 10 shown in FIG. 1 can be used formeasuring the over-the-air performance of the device under test 12 as afunction of temperature of the device under test 12. For this purpose,the device under test 12 is provided and placed within the enclosure 20.

Then, the atmosphere within the enclosure 20, for example thetemperature and/or the pressure, is adapted by guiding air into theenclosure 20 and/or by guiding air from the enclosure 20 via theatmosphere conditioning system 32 until a predetermined atmosphere isreached.

Once the intended atmosphere is reached, the atmosphere conditioningsystem 32 is disconnected from the enclosure 20 and the enclosure 20 issealed off by closing the at least one sealable opening 30 which waspreviously used for adapting the atmosphere in the enclosure 20.

As the device under test 12 is exposed to the atmosphere, the deviceunder test 12 has substantially the same temperature as the atmosphereafter a certain time as it is heated up or cooled down by the atmospherewithin the internal space 22.

Then, the over-the-air measurements intended can be performedappropriately. Accordingly, different application conditions can besimulated by the OTA system 10.

Since the enclosure 20, for example the internal space 22, is sealed offcompletely, the atmosphere can be maintained for long duration in astable manner during the testing.

Due to the movable positioning unit 48, the radiation performance of thedevice under test 12 can be tested for one, two or three dimensionsdepending on the test scenario applied.

Furthermore, the radiation characteristics or rather radiationperformances of the device under test 12 can be tested as function ofthe temperature of the device under test 12 itself, for example thetemperature of the antenna unit 42 as well as the temperature of theradio frequency circuit 44, by adapting the atmosphere to differentatmospheres, for example temperatures and/or pressures.

For instance, the OTA measurements are done for a first atmosphere(first ambient conditions) wherein the atmosphere is re-adapted byconnecting the atmosphere conditioning system 32 with the enclosure 20again for ventilation and/or changing the atmosphere within the internalspace 22.

Hence, the temperature and/or pressure may be varied for a second teststep of the testing scenario such that the device under test 12 can betested for different atmospheres in order to investigate the temperaturebehavior of the while device under test 12.

In some embodiments, the temperature behavior of the radio frequencycircuit 44 of the device under test 12 can be investigated by measuringthe radiation properties of the device under test 12.

Generally, the measurement antenna unit 18 used for testing the deviceunder test 12 may comprise at least one of a single antenna, an antennaarray and a hardware-based near-field to far-field transform unit.Hence, different antennas may be used for different testing purposes.

Various components, including the measurement device 14, the measurementunit 16, the measurement antenna unit 18, the control unit 34, theantenna unit 42, the frequency circuit 44, the positioning unit 48,etc., may include, in some embodiments, logic for implementing thetechnologies and methodologies described herein. This logic can becarried out in either hardware or software, or a combination of hardwareand software. In some embodiments, one or more of these componentsincludes one or more computing devices such as a processor (e.g., amicroprocessor), a central processing unit (CPU), a digital signalprocessor (DSP), an application-specific integrated circuit (ASIC), afield-programmable gate array (FPGA), or the like, or any combinationsthereof, and can include discrete digital or analog circuit elements orelectronics, or combinations thereof. In an embodiment, one or more ofthese components includes combinations of circuits and computer programproducts having software or firmware instructions stored on one or morecomputer readable memories that work together to cause an associateddevice to perform one or more methodologies or technologies describedherein.

The present application may also reference quantities and numbers.Unless specifically stated, such quantities and numbers are not to beconsidered restrictive, but exemplary of the possible quantities ornumbers associated with the present application. Also in this regard,the present application may use the term “plurality” to reference aquantity or number. In this regard, the term “plurality” is meant to beany number that is more than one, for example, two, three, four, five,etc. The terms “about,” “approximately,” “near,” etc., mean plus orminus 5% of the stated value. For the purposes of the presentdisclosure, the phrase “at least one of A, B, and C,” for example, means(A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C),including all further possible permutations when greater than threeelements are listed.

The principles, representative embodiments, and modes of operation ofthe present disclosure have been described in the foregoing description.However, aspects of the present disclosure which are intended to beprotected are not to be construed as limited to the particularembodiments disclosed. Further, the embodiments described herein are tobe regarded as illustrative rather than restrictive. It will beappreciated that variations and changes may be made by others, andequivalents employed, without departing from the spirit of the presentdisclosure. Accordingly, it is expressly intended that all suchvariations, changes, and equivalents fall within the spirit and scope ofthe present disclosure, as claimed.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. An over-the-air testsystem for measuring the radiation performance as a function oftemperature of a device under test having at least one antenna unit andat least one radio frequency circuit, wherein the over-the-air testsystem comprises: a measurement antenna unit; a measurement unit for atleast one of signal generation and signal analysis; an enclosure thatprovides an internal space for accommodating the device under test fortesting purposes in a sealed manner; and an atmosphere conditioningsystem that is configured to adapt the atmosphere within the internalspace, wherein the enclosure comprises at least one sealable opening viawhich the internal space is connectable with the atmosphere conditioningsystem to adapt the atmosphere within the internal space for thetesting, wherein, in an atmosphere conditioning operation mode of thetest system, the atmosphere conditioning system is connected to theenclosure via the at least one sealable opening in order to adapt theatmosphere within the internal space, and wherein, in a testingoperation mode of the test system, the atmosphere conditioning system isdisconnected from the enclosure and the at least one sealable opening issealed off such that the device under test is accommodated in theenclosure in a sealed manner.
 2. The over-the-air test system accordingto claim 1, wherein the enclosure is configured such that a gap isprovided between the device under test and the inner surface of theenclosure.
 3. The over-the-air test system according to claim 1, whereinthe atmosphere conditioning system comprises a control unit whichcontrols the atmosphere within the internal space.
 4. The over-the-airtest system according to claim 1, wherein the atmosphere conditioningsystem comprises a piping system for guiding at least one of air fromthe internal space and air to the internal space.
 5. The over-the-airtest system according to claim 1, wherein the at least one opening isconfigured to process at least one of an air stream into the internalspace and an air stream from the internal space.
 6. The over-the-airtest system according to claim 1, wherein the enclosure is made of aradio frequency neutral material.
 7. The over-the-air test systemaccording to claim 1, wherein the enclosure comprises an inflatablelayer.
 8. The over-the-air test system according to claim 7, wherein theinflatable layer is a balloon-like layer.
 9. The over-the-air testsystem according to claim 1, wherein the enclosure has at least twolayers spaced apart from each other such that an air gap is providedbetween both layers.
 10. The over-the-air test system according to claim1, wherein a positioning unit for the enclosure is provided.
 11. Theover-the-air test system according to claim 10, wherein the enclosure isplaced on the positioning unit.
 12. The over-the-air test systemaccording to claim 1, wherein the enclosure comprises an interface panelfor establishing connections between the device under test and peripherydevices.
 13. The over-the-air test system according to claim 12, whereininterface panel establishes cable connections between the device undertest and periphery devices.
 14. The over-the-air test system accordingto claim 1, wherein the measurement antenna unit comprises at least oneof a single antenna, an antenna array and a hardware-based near-field tofar-field transform unit.
 15. The over-the-air test system according toclaim 1, wherein a device under test is provided that has at least oneantenna unit and at least one radio frequency circuit.
 16. A method formeasuring the over-the-air performance of a device under test as afunction of temperature of the device under test, comprising: providinga device under test with at least one antenna unit and at least oneradio frequency circuit; placing the device under test in an enclosure;adapting the atmosphere in the enclosure by guiding at least one of airinto the enclosure and air from the enclosure via an atmosphereconditioning system until a predetermined atmosphere is reached, whereinthe atmosphere conditioning system is connected to the enclosure via atleast one sealable opening in order to adapt the atmosphere within theinternal space in an atmosphere conditioning operation mode;disconnecting the atmosphere conditioning system from the enclosure andsealing off the enclosure by closing the at least one opening used foradapting the atmosphere in the enclosure, thereby establishing a testingoperation mode; and performing the over-the-air measurements in thetesting operation mode.
 17. The method according to claim 16, wherein atleast one of the temperature and the pressure is adapted.
 18. The methodaccording to claim 16, wherein the over-the-air measurements areperformed in one dimension, two dimensions or three dimensions.
 19. Themethod according to claim 16, wherein the atmosphere in the enclosure isre-adapted by connecting the atmosphere conditioning system with theenclosure for at least one of ventilation and changing the atmosphere.20. An over-the-air test system for measuring the radiation performanceas a function of temperature of a device under test having at least oneantenna unit and at least one radio frequency circuit, wherein theover-the-air test system comprises: a measurement antenna unit; ameasurement unit for at least one of signal generation and signalanalysis; an enclosure that provides an internal space for accommodatingthe device under test for testing purposes in a sealed manner; and anatmosphere conditioning system that is configured to adapt theatmosphere within the internal space, wherein the enclosure comprises atleast one sealable opening via which the internal space is connectablewith the atmosphere conditioning system to adapt the atmosphere withinthe internal space for the testing, wherein the atmosphere conditioningsystem is not connected to the enclosure during the testing of thedevice under test, thereby ensuring that the atmosphere conditioningsystem does not affect the atmosphere during the testing as not gasexchange is enabled.